How do I readjust my disk tray

My dog knocked my disk tray out of alignment (it was open when she slammed into it). There are no broken parts and I was able to get the tray back in the grooves...but when it tries to close it hits the disk head. I'm guessing the tray is not aligned correctly with respect to the gears. I see your instructions for removing the tray and replacing it, but how do I realigh the gears with the tray?